MdeModulePkg/DxeIpl: Mark page table as read-only

[mirror_edk2.git] / MdeModulePkg / Core / DxeIplPeim / Ia32 / DxeLoadFunc.c

diff --git a/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c b/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c
index 96f57184447061b02831ac09cf755e857fcbb7b8..0ec60893ee316fb2a1aeabdb0059d1ec550437ef 100644 (file)
--- a/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c
+++ b/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c
@@ -99,7 +99,7 @@ Create4GPageTablesIa32Pae (
   NumberOfPdpEntriesNeeded = (UINT32) LShiftU64 (1, (PhysicalAddressBits - 30));\r
 \r
   TotalPagesNum = NumberOfPdpEntriesNeeded + 1;\r
-  PageAddress = (UINTN) AllocatePages (TotalPagesNum);\r
+  PageAddress = (UINTN) AllocatePageTableMemory (TotalPagesNum);\r
   ASSERT (PageAddress != 0);\r
 \r
   PageMap = (VOID *) PageAddress;\r
@@ -149,6 +149,12 @@ Create4GPageTablesIa32Pae (
       );\r
   }\r
 \r
+  //\r
+  // Protect the page table by marking the memory used for page table to be\r
+  // read-only.\r
+  //\r
+  EnablePageTableProtection ((UINTN)PageMap, FALSE);\r
+\r
   return (UINTN) PageMap;\r
 }\r
 \r
@@ -211,6 +217,41 @@ IsExecuteDisableBitAvailable (
   return Available;\r
 }\r
 \r
+/**\r
+  The function will check if page table should be setup or not.\r
+\r
+  @retval TRUE      Page table should be created.\r
+  @retval FALSE     Page table should not be created.\r
+\r
+**/\r
+BOOLEAN\r
+ToBuildPageTable (\r
+  VOID\r
+  )\r
+{\r
+  if (!IsIa32PaeSupport ()) {\r
+    return FALSE;\r
+  }\r
+\r
+  if (IsNullDetectionEnabled ()) {\r
+    return TRUE;\r
+  }\r
+\r
+  if (PcdGet8 (PcdHeapGuardPropertyMask) != 0) {\r
+    return TRUE;\r
+  }\r
+\r
+  if (PcdGetBool (PcdCpuStackGuard)) {\r
+    return TRUE;\r
+  }\r
+\r
+  if (PcdGetBool (PcdSetNxForStack) && IsExecuteDisableBitAvailable ()) {\r
+    return TRUE;\r
+  }\r
+\r
+  return FALSE;\r
+}\r
+\r
 /**\r
    Transfers control to DxeCore.\r
 \r
@@ -385,10 +426,7 @@ HandOffToDxeCore (
     TopOfStack = (EFI_PHYSICAL_ADDRESS) (UINTN) ALIGN_POINTER (TopOfStack, CPU_STACK_ALIGNMENT);\r
 \r
     PageTables = 0;\r
-    BuildPageTablesIa32Pae = (BOOLEAN) (IsIa32PaeSupport () &&\r
-                                        (IsNullDetectionEnabled () ||\r
-                                         (PcdGetBool (PcdSetNxForStack) &&\r
-                                          IsExecuteDisableBitAvailable ())));\r
+    BuildPageTablesIa32Pae = ToBuildPageTable ();\r
     if (BuildPageTablesIa32Pae) {\r
       PageTables = Create4GPageTablesIa32Pae (BaseOfStack, STACK_SIZE);\r
       if (IsExecuteDisableBitAvailable ()) {\r